Substituting (REF ) and [1]} into (REF ), we have
\({f_{{\gamma _k}}}\!\left( \gamma \right)\! = \!\frac{{{m_{fk}}^{{m_{fk}}}{{\left( {{m_{sk}} 1} \right)}^{{m_{sk}}}}{{\bar{z}}_k}^{{m_{sk}}}{\gamma ^{{m_{fk}} 1}}}}{{{{\left( {{P_{Ik}}{\eta _k}} \right)}^{{N_{Ik}}}}\Gamma \!\left( K \right){{\left( {{P_k}D_{{\rm {u}}k}^{ {\alpha _k}}} \right)}^{{m_{fk}}}}B\!\left( {{m_{fk}},{m_{sk}}} \right)}}I_1,\) 
